The situation is troubling news for the first-place Hawks. The Hawks have been the surprise of the NBA this season, dominating the Eastern Conference to a 59-19 record with an eight-game lead for first place.

Sefolosha hasn’t played a ton of minutes because of other injuries, but he’s one of the Hawks’ most important bench players and arguably their best perimeter defender.

With Sefolosha on the court, the Hawks have a 95.3 defensive rating. When Sefolosha is on the bench, that numbers falls to 102.6. The Hawks go from being the best defensive team in the NBA with Sefolosha on the court to being the 14th-best when he sits.

With the Eastern Conference likely being a three-team race between the Hawks, Cleveland Cavaliers, and Chicago Bulls, Sefolosha’s presence could be missed when Atlanta has to defend opposing wings like LeBron James or the Bulls’ Jimmy Butler. That duty now will almost solely fall on starting forward DeMarre Carroll, who will have to play extended minutes.

This is the worst possible time for the Hawks to have injury issues. On Monday, starting forward and leading scorer Paul Millsap sprained his shoulder and hasn’t played since.

The Hawks have had the first seed in the East locked up for most of the season. However, over the last month the Hawks are 9-6, ninth in offensive rating (sixth for the season), and 17th in defensive rating (eighth for the season).